This invention relates to the field of electronics where two types, or families, or electronic circuits must be interconnected. More particularly, integrated injection logic (I.sup.2 L) circuitry and linear circuitry. An example of such a situation would be an integrated circuit digital data processing system controlling an integrated circuit oscillator.
Various families of electronic circuits have been developed within recent years; within each one of these families the circuit elements themselves are compatible with each other. However, the occasion often arises where two families need to be interconnected with each other. Sometimes this interconnection can be done directly, but at other times some sort of interfacing is required to make the two families compatible with each other.
Of the families of circuitry one of the newest is integrated injection logic. Integrated injection logic is a digital logic family which has characteristics of low current and high packing density on integrated circuit chips. A discussion of I.sup.2 L circuitry and presently known interfacing circuits can be found in Electronics Magazine, Oct. 3, 1974, p. 111. Electronics is published by McGraw Hill, New York, New York, and the issue is Volume 48, No. 3.
One of the problems with prior art interface circuitry is that only logic functions are capable of being transferred by the interface circuit. However for many integrated circuit applications the interface circuit must be able to supply relative large amounts of current to compensate for manufacturing variations. This is not obtainable with prior art circuits without greatly increasing the size and complexity of the interfacing circuitry.
Accordingly it is the object of this invention to achieve interface between an I.sup.2 L circuit and a linear circuit with the minimum number of components.
It is also the object of the present invention to provide reference current levels of the I.sup.2 L circuitry; thereby providing compatibility between the two electronic families.
It is another object of this invention to provide I.sup.2 L current levels from high breakdown, high impedance sources.